This proposal requests continued support for a NINR funded study that had been entitled: Nutritive sucking: Physiological and Behavioral correlates. In the present proposal, we (1) deepen our analysis of feeding organization by integrating measures of sucking, swallowing and breathing over the course of full meals and (2) characterize the feeding patterns of another at-risk population - infants with congenital heart disease (CHD), and (3) relate feeding performance and energy expenditure to problems in growth and development over the first year of life in CHD infants. These infants are often difficult to feel, even when their surgery has improved their cardiac function. Indeed, the success of the surgery often unmasks their severe nutritional syndrome, failure to thrive (FTT). To address this important clinical problem, we propose to measure feeding performance and energy expenditures over the first hear of life in 120 infants who have undergone surgery during the first month of life to correct or palliate sever cardiac abnormalities and 60 healthy newborn controls. The specific aims of our proposed study are as follows: 1) to establish which aspects of feeding performance (e.g. suck/swallow/breathe coordination, temporal patterning of sucking with meals, suck pressure generation, adaptation to variation in flow rate) are most subject to disruption in CHD infant after corrective or palliative surgery; 2) to determine infants' pattern of oropharyngeal adaptation to variations in the flow rate through an artificial nipple, and whether flow rate adjustment represents a viable strategy for improving meal size outcomes; and 3) to determine the relative contributions of disrupted feeding organization and (potentially elevated) energy expenditure to unfavorable growth outcomes, i.e. (i) relate disrupted feeding to growth, (ii) relate energy expenditure to growth, and (iii) integrate energetic and feeding-performance characteristics in a predictive model of failure to thrive in infants with CHD. This study addresses what we believe is the central role of feeding organization in the nutritional status of this patient population; as such, it represents an approach toward early identification, based on feeding performance and energetic profiles, of infants most at risk for developing FTT by the age of one. The present work may offer prospects for targeted behavioral interventions involving modification of flow rates and paced feeds.